The cetacean populations along the Australian coast tell different stories at different scales. Some species are continuing the dramatic recovery from twentieth-century whaling. Some have stabilised at lower-than-historical numbers. Some show recent declines that researchers are still working to understand. The Q1 2026 data and the ongoing field programs provide a richer picture than was available even two years ago.

This is a working summary of what the recent monitoring data reveals, drawn from the published research, the major migration count programs, and the ongoing population studies.

Humpback whales

Humpback whales continue their long recovery trajectory, but with some new wrinkles.

The east coast humpback population, which migrates between Antarctic feeding grounds and Queensland calving grounds, has continued to grow. The most recent population estimates are above 40,000 animals and the species is now considered to have substantially recovered from the post-whaling lows.

The growth rate has been slowing relative to the earlier years of recovery, which is consistent with the population approaching pre-whaling carrying capacity. The slowing isn’t itself concerning — it’s what would be expected as a recovering population approaches its ecological limit.

The west coast humpback population has shown similar recovery, with current estimates also in the tens of thousands.

Two specific concerns are visible in the recent data. Vessel strike incidents have increased in absolute terms as both whale populations and vessel traffic have grown. Entanglement in fishing gear remains a significant cause of mortality and injury, with regional variation in the rates depending on the specific fishing pressures and the gear types.

Southern right whales

Southern right whales tell a more concerning story. The species was hit harder by historical whaling and the recovery has been slower and less complete than for humpbacks.

The southern Australian population shows recovery but with concerning patterns. The number of breeding females visible at known calving aggregation sites has been variable year to year, with some recent years showing lower numbers than expected. The reasons aren’t fully understood — possible explanations include changes in oceanographic conditions affecting feeding, changes in the timing of migration, or genuine population effects.

The Head of Bight aggregation in South Australia, one of the most-studied calving sites, has shown lower numbers in recent years than were typical in the 2010s. The recent surveys haven’t yet established whether this is a temporary anomaly or a pattern that would indicate broader concern.

Blue whales

Blue whale populations remain at low levels. The Bonney Upwelling area off western Victoria continues to be a major feeding aggregation for the pygmy blue whale subspecies, with seasonal aggregations of hundreds of animals.

The actual population numbers for blue whales in Australian waters remain uncertain. The animals are widely distributed, the surveys are difficult, and the historical baselines are uncertain. The species is recognised as still recovering from whaling impacts and the management posture remains conservative.

The acoustic monitoring programs continue to detect blue whale calls across substantial areas of Australian waters. The acoustic data complements the visual surveys and provides a richer picture than either method alone.

Sperm whales

Sperm whale populations in Australian waters are difficult to survey because of the species’ offshore distribution and deep diving behaviour. The available data suggests stable populations in the offshore waters where the species concentrates, with the historical recovery pattern from whaling broadly continuing.

Specific concerns about sperm whale populations include vessel strikes in shipping lanes and the impacts of underwater noise pollution on the species’ acoustic communication. The mitigation measures for both have been progressing slowly.

Bottlenose dolphins

Bottlenose dolphin populations are heterogeneous across the Australian coast, with multiple distinct populations rather than one continuous distribution. The Indo-Pacific bottlenose dolphin and the common bottlenose dolphin both occur in Australian waters with overlapping but distinct distributions.

The major bay and coastal populations have been monitored for years and show generally stable numbers. The Port Stephens population, the Shark Bay population, the various Queensland coastal populations all have ongoing monitoring programs.

Some specific populations show concerning trends. The Burrunan dolphin in Victorian waters, recognised as a distinct species, has very low population numbers and faces ongoing pressure from coastal development and water quality issues. The species is considered at high conservation risk.

Common dolphins

Common dolphins are widely distributed across Australian waters and are typically seen as having larger and more stable populations than the more localised bottlenose populations. The aggregations of hundreds or thousands of animals seen offshore reflect the species’ more pelagic ecology.

Specific monitoring programs are limited because of the species’ wide distribution and offshore preferences. The general picture from the available data is of stable populations.

Killer whales

Killer whales in Australian waters are seasonally visible at several locations including the Bremer Canyon off Western Australia, where summer aggregations have been documented for over a decade. The population dynamics of these aggregations are still being worked out.

The Bremer Canyon aggregations have grown into a tourism economy with associated regulatory and management challenges. The monitoring of how the tourism is affecting the animals is ongoing.

Dugongs

Dugongs are not cetaceans but are often discussed alongside them as a charismatic marine megafauna. The dugong populations in Australian waters are the largest globally, with the major populations in northern Queensland, the Torres Strait, and Western Australia.

The Q1 2026 dugong population data shows stable but pressured populations. Specific pressures include seagrass habitat impacts (cyclone damage, sediment effects), vessel strikes, and gillnet fishing impacts in specific areas. The conservation management for dugongs is ongoing across multiple jurisdictions.

What’s worth watching

Several specific developments through the rest of 2026 will be worth tracking.

The southern right whale calving counts at the major aggregation sites for the 2026 season. Continuation of the recent lower numbers would be more concerning; a return to earlier numbers would suggest the recent low years were anomalies.

The vessel strike trends across the major shipping lanes. The combination of recovering whale populations and increasing vessel traffic produces structural pressure that needs management attention.

The fishing gear entanglement data. The improved entanglement response programs in some states have been showing benefits; the slower-developing programs in others remain a concern.

The acoustic monitoring data from the offshore deep-diving species. The acoustic methods continue to mature and produce richer data on species and populations that are hard to survey visually.

The continuing impacts of marine heatwaves on prey species and food web dynamics. The cetacean populations depend on healthy prey populations; the climate-driven changes to those prey populations are a longer-term concern.

The conservation picture

The aggregate picture for Australian cetaceans is mostly positive — the historical whaling impacts have been substantially reversed for the most affected species, and the populations are at or approaching healthier levels than in living memory.

The ongoing pressures — vessel strikes, entanglement, plastic pollution, noise pollution, climate-driven habitat changes — remain real and require continued management attention. The conservation infrastructure across Australian and adjacent jurisdictions has continued to develop.

The challenge for the next decade is managing the interactions between recovering populations and intensifying coastal and offshore human activity. The whale populations will continue to grow, the boat traffic will continue to grow, the climate-driven changes will continue to affect prey distributions. The management frameworks have to keep up with the changing operating reality.

The data from the Q1 2026 surveys is broadly encouraging on the population trajectory. The work continues on the issues that need management attention. The longer-term picture depends substantially on the trajectory of the underlying climate and ocean health, which is the harder problem.